1. Field of the Invention
A lens barrel that includes a lens in a body and an associated methodology of actuating the lens barrel in an appointed direction are provided. A camera, a digital camera, a portable information terminal and an image input device including the lens barrel are also provided.
2. Discussion of the Background
Whether a lens barrel is in a state in which it is loaded in a camera body or whether a lens barrel is in a state in which it is divided, as, for example, a single-lens reflex camera, by a camera body, the lens barrel might in either case be shocked if it is dropped by mistake, or if it collides with other things.
In a state in which the lens barrel is configured to photograph, for example, if a cam follower or a crest of a helicoidal screw of the lens barrel are compromised by a shock, or if a cam groove or a groove in a circumferential direction of the lens barrel are transformed by a shock, it may make it more difficult to smoothly operate a transfer of the taking lens which is performed by the cam follower and the cam groove or by the crest of a helicoidal screw and the groove in a circumference direction.
Japanese registration patent 3,288,918 (Japanese Patent Publication No. 09-230192) describes that because an end of side after a cam groove of a cylindrical member has a shocked aspect, a cam follower that is made from a ring member and a metallic pin, it can be prevented from damaging at the time of a shock.
Japanese Patent Publication No. 2003-344744 describes that because a tip inside of a cam groove of a cylindrical member holds a metal reinforcement link, it can be prevented from being damaged at the time of a shock.
Japanese registration patent 2,864,363 (Japanese Patent Publication No. 08-211272) describes that it makes dampen power added to a moving frame through two supporting member and it is includes a guide pin.
However, although the above-noted documents describe the cam follower and the reinforcement of the cam groove, they do not describe a prevention of destruction when a crest of a helicoidal screw on the lens barrel is shocked in an optical axis direction.